Basic lead naphthenate



Patented May 9, "1939 PATENT OFFICE BASIC LEAD NAPHTHENATE Kenneth E.Long, South Euclid, Ohio, assignor to The Harshaw Chemical Company,Cleveland, Ohio, a. corporation oi Ohio No Drawing.

Application October 30, 1933,

Serial No. 695,955 1 Claim. (c1. 260-435) naphthenate, etc., sold to thetrade as such or under various trade names, are used in the paint,varnish, and printing ink industries as siccatives and are also used ingrease making and in waterproofing compounds, etc. The usual commercialpractice in preparation of these salts or soaps consists ofsaponification of a fatty acid or its glyceride with alkali andprecipitation of the lead soap with a soluble lead salt such as theacetate or nitrate. Another method consists of combining directly a leadcompound, such as litharge, with a fatty acid, in a suitable kettle orcontainer, with the aid of heat. This reaction is carried out at atemperature from 100 C. to 250 C. Water formed by the reaction isexpelled at the time of formation as water vapor or $0 steam. There isno great difference between the products made by either method with theexception that the fused products are usually darker in color andcontain'some free fatty acid, as it is difficult to bring into contact,in a fusion of this 85 type, every particle of litharge with the fattyacid. By either method the metallic content is at best substantially nothigher than the acid combining equivalent.

In accordance with the present invention, a

- 40 lead oxy-compound, viz.; litharge, lead hydroxide or hydrated leadoxide is intimately mixed at a temperature below 100 C. with an organicacid of the fatty acid type which is water-insoluble or at leastsparingly soluble. During this mixing a reaction takes place between theacid and the lead oxid with consequent formation of water. There is arise in temperature of the reacting mass but conditions are controlledso that the heat generated is not sumcient to expel the wa- 'terliberated by the reaction. In contradistinc tion to the general or oldpractice, I have found that by my method I can introduce litharge inamounts substantially in excess of the theoretical combining ormolecularequivalent. I have found also that all of the lead so introduced is inchemical combination with the acid. As a further step, the temperatureis raised to complete the reaction and drive off the water of reaction,or the water may be removed by any suitable means.

The mixing of the lead compound and acid must be positive and thoroughto prevent formation of lumps of partially reacted material which arenot easily incorporated if once formed. One effective way of thoroughmixing is by grinding the desired mixture of acid and lead compound onink-grinding rolls.

The following examples are illustrative of the process:

I I. 100 parts of napthcnic acid with an acid value of about 250 aremixed with about 71 parts of litharge, being thoroughly incorporated, ason ink-grinding rolls, the temperature being maintained below 100 C.Reaction sets in readily and the disappearance of the litharge soontakes place With the substantial completion of the reaction, thetemperature is raised to above 100 C., and lessthan 200 C., and waterformed is driven off. The product is a lead soap containingapproximately 40 per cent of lead. It is a soft, gummy solid, soluble inmineral oil'naphtha, xylol, toluol, and oils such as linseed oil, etc.

II. 100parts of synthetic fatty acids made by the oxidation of petroleumhydrocarbons and having an acid value of about 360, are mixed with about115 parts of lead oxide, PbO, with thorough incorporation, thetemperature being maintained below 100 C. After thorough mixing, andprogress of the reaction, the temperature may be raised to 100 C., ormore, to remove the water of reaction. The product is a basic lead saltcontaining approximately 52 per cent of lead. It is a waxy solid solublein xylol, toluol, also oils such as linseed oil.

III. parts-of synthetic fatty acids made by the "oxidation of petroleumhydrocarbons and having an acid value'of about 360, and about 40 partsof napthenic acid with an acid value of about 250, are mixed with about71 parts of lead oxide, PbO, as 'afore-described, the temperature beingmaintained below about C., and being finally raised thereabove to driveoff water of reaction. The product is a basic lead salt containingapproximately .40 per cent lead. It is a soft, pasty solid, readilysolublein solvents such asabove-enumerated.

IV. 100 parts of linseed oil fatty acid with an acid number of about190, are mixed with about 71 parts of lead oxide, PbO, for instance bygrinding on rolls, to a smooth paste at ordinary temperature. Thetemperature is then slowly raised to about 100 C., and the reaction iscompleted, and the temperature is then further raised to about 180 C. todrive of! water. Other organic acids can similarly be reacted, such asfatty oil acids such as oi linseed oil, flsh oil, soy bean oil, cornoil, tung oil, etc. Where dealing with acids oi rather high molecularweight, the reaction may be started particularly advantageously by thepresence of a small or catalytic amount of water. For instance, bymoistening the litharge or the like with water as it is mixed with theacid, or by adding a small quantity of water to the mixture. On iaddition of the water, the reaction promptlmistarts. In most cases, andparticularly with loweif"mnlecular weight fatty acids, reaction sets inwithout addition of water, and water is in fact formed in the reaction.By maintaining the tempera- 20 ture careiully below 100 C., theadvantageous progress oi reaction is had, as already noted, and thetemperature is to be raised ultimately, more particularly for thepurpose of driving oi! water.

Other modes of applying the principle of the invention may be employed,change being made as regards the details described, provided thefeatures stated in any of the following claims. or the equivalent ofsuch, be employed.

I therefore particularly point out and distinctly claim as myinvention:-

A lead salt product of napthenic acid containing combined lead to theextent of more than one combining equivalent weight 0! lead to eachcombining equivalent weight of acid but not substantially over suchproportion as involved in aratio oiabout71partsoiPb0to 100partsotnaphthenic acid of acid value about 250, and

being thereby basic but below maximum polible baslclty.

KENNETH E. mm. m

